Multichannel Systems STG3008-FA Manual - Manual (Page 59)

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10 Synchronizing Events
10.1 Digital Output Signals (Sync Out)
The output of the digital Sync Out output is a 3.3 V TTL signal. A logic state of 1 means 3.3 V,
and a logic state of 0 means 0 V. Please note that the digital output is about 15 μs faster than
the analog output. This small offset is generally sufficient to make sure that the Sync Out signal
precedes the stimulation, which is important for synchronizing events.
You can program the output signal of the Sync Out channel in the same way as the analog output
signals, but due to the nature of a digital signal, only values of 0 and 1 are allowed. A Sync Out
signal is generated each time when the STG is started.
The output signal can be used for triggering external devices, for example, the any data
acquisition devices.
Note: Please note that if you use it for triggering the MC_Card, you should use output signals that
have a
duration of at least 200 μs . Otherwise, it can happen that the MC_Card ignores trigger
events.
The Sync Out output is active when the STG is started by pressing the Start / Stop button,
or by using the software command Start on the STG menu.
If you are using the Trigger In input for starting the STG, ther Sync Out channel is controlled
by the Trigger In channel. Sync Out 1 is active when Trigger In 1 is triggered.
If you use the Repeat feature in the Trigger Settings dialog box, the Sync Out signal is repeated
as well as the selected analog output signals.
Note: No Sync Out signal is sent when the STG is stopped on a trigger event or by pressing the
Start / Stop button, that is, if the trigger event occurs or the button is pressed when the STG
has still been active.
10.2 Triggering Stimulation (Trigger In)
The external trigger input has to be a TTL signal of at least 40 +/- 10 μs length. TTL pulses
shorter than that may not be recognized by the stimulus generator.
A TTL pulse is defined as a digital signal for communication between two devices. A voltage
between 0 V and 0.8 V is considered as a logical state of 0 (LOW), and a voltage between 2 V
and 3.3 V means a 1 (HIGH). It is the same kind of signal as the output signal of the Sync Out
output of the STG.
In STG3008-FA there is one Sync Out output for one trigger input. You can assign the Sync Out
and the analog channels to the trigger input in the Trigger Settings dialog box. The default
settings is that Sync Out 1 is active when Trigger In 1 is triggered. See also "Digital Output
Signals" for more information on the Sync Out channel.
The Sweep status display (LED Start / Stop buttons) in the main window of the
program shows active sweeps that were started by the trigger. That means, the status lamp that
corresponds to trigger 1 lights red as long as any channel triggered by trigger 1 is active. Please
note that the number of the analog output channel is irrelevant, the Sweep status lamp refers
only to the trigger. Example: Assume that channel 4 is assigned to trigger 1. When channel 4
is active, the Sweep lamp lights red , because the Sweep lamp refers to trigger 1.